1. Field of the Invention
The present invention relates to immersion probes for analyzing molten metals and, more particularly, to shock absorbing immersion probes.
2. Description of the Prior Art
Immersion probes are currently used in the metal-making art for analyzing or detecting various characteristics of metal. Characteristics, such as temperature, viscosity, the temperature of solidification of the molten metal (liquidous arrest temperature), and carbon, oxygen and other component content, to name a few, are preferably ascertained in situ while the metal is in its molten state. Because of the high temperatures at which molten metals are maintained, analyses in the molten metal environment necessitate devices that can withstand such high temperatures without affecting their functionality during the immersion period.
Examples of probes for detecting characteristics of molten metals include those probes disclosed in U.S. Pat. Nos. 3,643,509, 3,656,338 and 4,557,152, for example. Generally, immersible probes comprise an elongate body defining a chamber in which certain detecting means may be housed, such as thermocouples and sampling chambers and other molten metal detecting devices. To protect the detecting means from the intense heat of the molten metal environment, the body typically comprises a fire-proof material, such as quartz, ceramic, heat-resistant cement, silica, carbon, graphite, sintered aluminum oxide, zirconium oxide, or magnesium oxide, or agglutinated sand. These materials, and their method of fabrication, are generally costly and, consequently, an immersion probe made therefrom is relatively expensive.
While these materials exhibit excellent heat-resistant properties, they are brittle and relatively fragile and may be cracked or otherwise damaged when subjected to mechanical shock forces or impact loads, such as when they are dropped or struck against a hard object.
In the course of normal use, an immersion probe is typically coupled to means for lowering and raising the immersion probe into and out of a molten metal bath. Generally, such raising and lowering means also comprises means for electrically coupling the detecting means in the immersion probe to remotely located processing or recording means, where characteristics of the molten metal bath may be examined by metal processing operators.
The immersion probe or lance is generally coupled to or plugged into a reciprocally receiving coupling device, such as a sub-lance or lance holder. These and other reciprocally receiving coupling devices are well known in the art and are widely used for quick coupling and uncoupling of such immersion probes. Once such probes are received within such coupling devices and prior to immersion into the molten metal, an operator generally performs a test to confirm that the probe has been properly electrically coupled and that the detecting means are properly functioning.
Occasionally, the immersion probe is not properly coupled because of bent or damaged couplings or contacts, incomplete electrical contact, or mechanical or other malfunctions. When the operator performs a pre-immersion test, the probe is indicated as being defective, even though the problem may be due only to improper engagement of electrical contacts. Because timing is often critical in metals-processing, it is normal for the metal processing operator to immediately reject the immersion probe and to couple another probe to avoid delay.
A rejected immersion probe is typically dropped into a retrieval area via a rejection chute, which directs the rejected immersion probe to an area where the probe comes to rest. It is common for the immersion probe to be damaged during its travel through the rejection chute because of the impact loads imposed on the probe body while moving, especially where (as is common) the probe stops abruptly at the lower end of the chute. The brittle body of the probe and particularly the fragile detecting means within the probe (generally positioned at the lower end of the probe) are often broken as a result of such impact, thereby precluding any further use for the probe.
A metal processing operator, while attempting to successfully couple an immersion probe, often rejects (and thereby destroys) several immersion probes until successful coupling is achieved. Because of this procedure, a large quantity of fully operable probes may be needlessly destroyed, resulting in unnecessarily increased costs.
The present invention overcomes many of the disadvantages inherent in the above-described immersion probes by providing shock absorbing means for absorbing impact loads imposed upon the immersion probe. The shock absorbing means of the present invention can be easily and relatively inexpensively attached to or molded onto the immersion probe. In addition, the shock absorbing means of the present invention does not substantially interfere with the detecting or analyzing means in the immersion probe. Moreover, use of the present invention results in considerable monetary savings by eliminating or lessening the damage to immersion probes caused by impact loads imposed upon the probe body, thereby permitting re-use of operable probes, which have been rejected due to minor coupling problems.